Theoretical insights into electrochemical CO2 reduction mechanisms catalyzed by surface-bound nitrogen heterocycles

John A. Keith, Emily A. Carter

Research output: Contribution to journalArticlepeer-review

47 Scopus citations

Abstract

We propose a novel and general reaction mechanism to explain the unique performance of nitrogen-heterocycle-promoted (photo)electrochemical CO 2 reduction reactions. This mechanism is based on observations from recent computational and experimental studies of pyridinium-catalyzed CO 2 reduction. Herein we report pKas and standard reduction potentials of species adsorbed on GaP photoelectrodes derived from first-principles quantum chemistry computations. We show that on GaP surfaces, proton reduction or pyridinium reduction is energetically unfavorable even at very negative electrode potentials. However, it is thermodynamically favorable to convert a surface-bound pyridine into a 2e- reduced species such as dihydropyridine at less negative applied potentials. Intriguingly, these transient 2e- reduced species share a similar chemical moiety as some biological redox catalysts (e.g., NADH), and their reduction potentials are similar to the thermodynamic redox potentials that would convert CO2 to a variety of products.

Original languageEnglish (US)
Pages (from-to)4058-4063
Number of pages6
JournalJournal of Physical Chemistry Letters
Volume4
Issue number23
DOIs
StatePublished - Dec 5 2013

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Physical and Theoretical Chemistry

Keywords

  • CO conversion
  • density functional theory
  • electrocatalysis
  • reduction potentials
  • renewable energy

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